In general updating a screen of a WEB application, the entirety of data being displayed on the screen is reloaded and data after the updating is obtained.
The accompanying drawing FIG. 1 is a drawing illustrating a scheme of automatically updating a screen of a Web application.
Examples of automatically updating a screen are the following three schemes (1) to (3) illustrated in FIG. 1. The schemes (1) to (3) in FIG. 1 each display a Dashboard panel displaying a usage status and capability information of, for example, a storage device, and segment the screen into four blocks A-D.
The scheme (1) illustrated in FIG. 1 is a pull scheme in which the entirety of the screen being displayed (in other words, the entirety of displayed data) is periodically reloaded.
The scheme (2) illustrated in FIG. 1 is a pull scheme in which the displayed data is reloaded in units of blocks at respective reloading intervals determined by considering a frequency of updating of each block of the displayed data.
The scheme (3) illustrated in FIG. 1 is a push scheme in which the server transmits the updated data to the client terminal and each updated block is reloaded. The number of times of reloading is increased for data having a high updating frequency to increase the Input/Output (I/O) load as compared to the pull schemes. Therefore, the scheme (3) of FIG. 1 is suitable for reloading data having a low updating frequency.
[Patent Literature 1] Japanese Laid-open Patent Publication No. HEI 9-244993
However, the scheme (1) of FIG. 1 reloads a screen displaying there on data not updated and has a possibility of transferring also non-updated data.
Although reducing an amount of transferred non-updated data as compared to the scheme (1) of FIG. 1, the scheme (2) of FIG. 1 does not completely transfer non-updated data.
The scheme (3) of FIG. 1 transfers updated data from the server to the client terminal, and reloads the transferred updated data, and therefore has no possibility of transferring non-updated data.
However, the scheme (3) of FIG. 1 has a possibility of transferring updated data of a block not being currently displayed on the screen.
The accompanying drawing FIG. 2 is a diagram illustrating a problem of the scheme (3) of FIG. 1.
As illustrated in FIG. 2, in cases where the data 1 on the block B of the display screen is updated and the block B is reloaded, the block D, which has a dependent relationship with the block B because both blocks B and D have the data 1, may not be updated. This causes inconsistency of data between the block B and the block D.